Abstract WE567: Population Attributable Fractions of Prognostic Factors Associated with Long-Term Risk of Stroke After Transient Ischemic Attack or Minor Stroke: Systematic Review and Meta-Analysis

Introduction: Patients who have had a transient ischemic attack (TIA) or minor stroke have an increased of risk of stroke for at least the next 10 years. Identifying key prognostic factors and understanding their contribution to long-term stroke risk is essential for enabling more targeted and effective secondary prevention strategies. We therefore aimed to estimate the population attributable fraction (PAF) of prognostic factors associated with long-term risk of stroke in patients with TIA or minor stroke. Methods: We searched MEDLINE, Embase, and the Web of Science (from inception up to August 2025) for observational studies including patients with TIA or minor stroke that evaluated prognostic factors for subsequent stroke over a follow-up period of at least one year. We used random-effects meta-analysis to determine, for each factor, the pooled prevalence and hazard ratio for long-term stroke risk, adjusted for relevant confounders. We then estimated the pooled PAF for each factor using Levin's formula: p(aHR-1)/[1+p(aHR-1)], where p is the pooled prevalence of the factor and aHR is the pooled adjusted hazard ratio. Results: Of the 14732 records identified, we included 23 studies comprising 83,597 patients (mean age 65-71 years; 52-60% male patients). The figure shows the pooled prevalence, adjusted hazard ratio, and the corresponding PAF of each factor. Of the non-modifiable factors, an initial minor stroke (vs. TIA) accounted for the largest PAF (28.0% [95% CI], 10.1-47.6]), followed by paresis (22.0% [3.8-43.4]), any infarct on neuroimaging (19.0% [5.0-38.9]), aphasia or dysarthria (14.0% [7.0-25.0]), male sex (13.0% [7.8-18.7]), and history of stroke or TIA before the index event (12.0% [5.2-21.4]). Of the modifiable factors, hypertension accounted for the highest PAF (19.3% [95% CI, 8.4-31.6]), followed by etiologic stroke subtypes such as small vessel disease (16.8% [5.0-34.3]), cardioembolism (14.6% [3.1-33.5]), and large artery atherosclerosis (13.2% [5.1-25.5]); smoking (11.1% [1.0-30.7]), ischemic heart disease (10.7% [2.8-22.9]), diabetes mellitus (7.7% [3.1-14.1]), and atrial fibrillation (3.8% [0.3-9.9]). Conclusion: We have quantified the impact of several key factors on the long-term risk of stroke, taking into account their prevalence and relative magnitude of association. This information can aid in developing and implementing targeted interventions to better prevent future strokes in patients who have had a TIA or minor stroke.